It is known that, upon running on a landing runway further to a landing (or a decision to interrupt a take-off), the deceleration (or the braking) of an aircraft is achieved, either manually and directly by the pilot using the brake pedals, or by an automatic braking system slaving a fixed deceleration, preselected by the pilot before landing, via a push button or an electromagnet rotary button, according to one of a plurality of different braking modes.
Now, such braking systems, either manual or automatic, have no awareness of the topographic reality of the landing runway (length, width, etc.) on which the landing is achieved.
From FR-2,817,979 and FR-2,857,468, devices are known for automatically controlling the deceleration of an aircraft upon a running phase, allowing such a drawback to be partially overcome. Such known devices allow, indeed, the crew of an aircraft to select an exit on the landing runway and to manage, automatically and optimally (assistance to selecting an exit being realistic and compatible with the known landing performance, minimization of the occupation time for the runway, minimization of the required braking energy, improvement of the comfort) the deceleration of the aircraft upon running at landing, until the selected exit is reached. Consequently, in normal operational conditions, optimally reaching such an exit occurs by means of such usual devices.
Furthermore, it is known from FR-2,897,593 a process and a system for supplying, upon a landing, right before the aircraft contacts the landing runway, a piece of information whether landing will be long or not, leaving time (if applicable) to take actions allowing the drawbacks of a long landing to be overcome. To this end, the altitude of the aircraft is measured, the horizontal distance separating said aircraft from the proximal end threshold of the landing runway is calculated, and, from this altitude and this horizontal distance, as well as from an approach angle, an estimated ending position is determined of said aircraft on said landing runway.
Moreover, US-2004/0,167,685 contemplates calculating a critical point on the landing runway, beyond which landing can lead to the runway being passed, and emitting a warning if the current descent axis of the aircraft reaches the runway beyond this critical point.
The present invention, more particularly, aims at warning the crew of the aircraft (being provided with an automatic braking system) against a risk of longitudinal runway excursion, upon running on this runway upon landing.
It is known that, upon landing, a problem may occur at the level of the normality of the landing conditions and their management by the crew of the aircraft. Indeed, before starting a flight, the crew should make sure that landing of the aircraft on the destination airport is possible, that is, that the expected landing performance, combined with expected exogenous conditions (meteorology, knowledge of the destination airport, the crew's experience, etc.) are compatible with the length of the landing runway available at the level of said destination airport.
However, it is possible that meteorological conditions become altered while landing is performed (occurrence of heavy rains, high wind gradients, etc.) making then difficult for the crew to perform landing until the aircraft stops on the available length of the landing runway being used (or even, obtaining a speed being compatible with taking an exit the aircraft is supposed to follow). Under such conditions, a risk of longitudinal runway excursion could become significant.
Now, such a risk of a runway excursion is nowadays integrally managed by the crew, without any assistance, nor automation, thanks to their experience, their training and a good preliminary preparation of the flight, which is not satisfactory.
In addition, when the aircraft is provided with an automatic braking system, it is possible, in particular considering the previous conditions, that the crew selects on said automatic braking system an inappropriate braking mode. The most problematic case is the selection of an insufficient braking mode (that is, generating too low a deceleration), that could in particular increase the risk of a runway excursion if the pilot does not react on time upon running.
The present invention aims at solving these drawbacks. It relates to an assistance process for piloting an aircraft upon a landing phase, allowing, in particular, the crew of the aircraft to be warned against a risk of longitudinal runway excursion upon running on this runway, said aircraft being provided with an automatic braking system that is able to brake automatically the aircraft on the ground depending on a selected braking mode, said automatic braking system comprising a plurality of different braking modes respectively performing different strength brakings.